Facsimile recorder



w. G. H. FlNCH Filed Sept. 22,1942

'13 Sheets-Sheet l BY WILLIAM G. 'fi F'T y 1945- v w. G. H. FIN-CH 2,374,673

FACSIMILE RECORDER WILLIAM "PK F IK'FCH ATTQRNE y 1945. w. G. H. FIN-CH 2,374,673

FACSIMILE RECORDER Filed Sept. 22, 1942 15 Sheets-Sheet 5 7.; mamma illlllllllll li h,

WILLIAM G.IT1V.HFWCH Wm ATTORNEY.

May 1, 1945. w. s. H. FINCH FACSIMILE RECORDER Filed Sept. 22, 1942 13 Sheets-Sheet 4 FIG-8.

INVE

BY WILLlAM G. H. Fifi cH y 1945. w. G. HJFINCQ 2,374,673

FACSIMILE RECORDER Filed Sept. 22, 1942 13 Sheets-Sheet 5 BY WILLIAM G. fiY fi fifiH I ATTORNEY. I

May 1, 1945.

w. G. H. FI NCH FACSIMILE RECORDER Fiied Sept. 22, 1942 13 Sheets-Sheet 6 INVENTOR.

H. FINCH WILLIAM G.

y 1945. I w. G. H. FINCH 2,374,673

FACSIMILE RECORDER Filed Sept. 22, 1942 13 Sheets-Sheet 8 FIG-2.22.

WILLIAM G. W fiFfcH BY W ATTORNEY.

y 1, 1945. w. H. FINCH 2,374,673

FACS IMILE RECORDER Filed Sept. 22, 1942 13 Sheets-Sheet 9 BY WILLIAM G. HYWEH y 1, 1945. w. G. H. FINCH 2,374,673

FACSIMILE RECORDER Filed Sept. 22, 1942 13 Sheets- Sheet 10 VENTOR.

wmAM G. a. HNCH May 1, 1945.

W. G. H. FlNCH FACSIMILE RECORDER Filed Sept. 22, 1942 13 Sheets-Sheet 11 790 FIG.29.

WILLIAM G. F'1 FTKFCH 4 ATTORNEY.

y 1945. v w. G. H. FINCH 2,374,673

' FAGSIMILE RECORDER Filed Sept. 22, 1942 13 Sheets-Sheet 12 Fleas WILLIAM G. HY FTfiEIH ATTORNEY.

Patented. May I,' 1 945 Finch Telecommunications, Inc., Passaic, N. J., acorporation of Delaware Original application Ma 334,404. Dividedand y this 10, 1940, Serial No. application September 22, 1942, Serial N0. 459,319

'13 Claims; (Cl. 1786.6)

My present invention is a division 01' the application Serial No. 334,404,

incrder to await any particular synchronizing signal.

Heretofore in the operation of facsimile apparatus and particularly of facsimile receivers, it has been necessary in order to obtain line by line synchronism in line byline scanning to'halt some ing apparatus to scanning excursion simultaneously with the commencement of the scanning excursion at the transmitting end.

Accordingly it was necessary to design the apparatus so that thescanning means itself was brought to a stop at the end the transmitting apparatus in order to ensure the receiving apparatus would be ready for the receipt of the next synchronizing impulse.

The difficulties which arose by reason of the necessity of haltingthe operation of the receiving apparatus pending the receipt of the synchronizing impulse were present in each of the of a scanning cycle (preferably three) were mounted upon a chain and wherein the chain was supported by a pair of oppositely disposed sprockets which in turn were driven from the motor or other source of power, it was necessary to bring the drive shaft of the sprockets, the sprockets themselves, and the chain to a stop at the end of each scanning excursion in order to bring the stylus to a stop 1 and then to bring all. of these elements into movement once more immediately upon the receipt of the synchronizing impulse.

Likewise in the case of the stylus mounted upon an oscillating arm wherein the oscillating arm was continuously reciprocated back and forth, scanning on its excursion in one direction and returning in the opposite direction while the paper advanced; and wherein the oscillating arm was driven in any suitable manner by, for instance, a cam connection to a shaft, it was necessary to bring the shaft, cam and oscillating arm, to a stop immediately before the commencement of the scanning excursion in order to await the synchronizing impulse and then to bring all of these elements into motion once more immediately upon receipt of the synchronizing impulse.

The difliculty arising from the necessity of bringing all of these elements to a stop was not merely academic. In many cases of facsimile reception there are a hundred or more scanning lines to an inch and it is important that adjacent scanning ,linesshould not overlap.

It is further important that the individual facsimile impulses be properly spaced with respect to each other in order to obtain clear definition in the received picture.

Accordingly any even slight vibration inherent in the operation of the reception apparatus might tend seriously to mar Accordingly in prior facsimile apparatus it was essential that the apparatus be mounted on a heavy cast iron base and it was further useful to incorporate therein various complicated shock absorbing devices which would tend to inhibit whatever vibration necessarily resulted from the continuously recurrlng'starting and stopping of masses which, with respect to the size of the actual scanning stylus or beam were relatively reat.

This same difliculty was present with equal if not greater force in the light beam scanning reception ap aratus wherein the light beam traversed a reception drum longitudinally while the drum revolved. In this case it was neces- Sary not merely to bring the light beam scanthe picture.

nine apparatus itself to a stop but also to bring the receiving drum to a stop upon the completion of a scanning line and immediately before the inception of the next scanning line in order to await the receipt of the synchronizing impulse.

A second and equally important object of the present invention is to make it possible for virtually all of the moving parts of the receiving apparatus to maintain their constant movetime relying upon the ment while at the same synchronizing impulse to initiate the actual scanning operation. Another object of the present invention is to so mount and relate the actual scanning member itself to the various other moving parts that it is only the relatively small mass of the actual stylus or other scanning element which must be stopped or the motion of which must be changed in order to obtain proper synchronization.

Still another object of the invention is to obtain proper synchronization while the moving part of the receiving scanner may maintain constant uninterrupted unchanged movementj Still a further object of the present invention is to provide a synchronizing apparatus wherein the speed of the receiving apparatus may be cutdown to almost that of the transmitting apparatus.

Still another object of the present invention is to provide a means for obtaining automatic phasing at the start of the picture transmission and for automatically phasing the receiving apparatus at various selected intervals controllable from the transmitting station.

Since in many cases, facsimile receiving apparatus is to be used in the home by unskilled operators, it is essential that virtually all of the operations thereof be either greatly simplified or if possible, controlled from station.

Accordingly, the automatic phasing means herein provided will increase the utility of this Furthermore, the autoprovided may be apparatus in the home. matic phasing means herein the transmitting arranged to coact with the scanning element in order to reposition the scanning element with respect to its drive apparatus at selected intervals-in order to ensure that the scanning element will remain aligned with its driving elements.

There are many other objects and uses of the present invention part of'which will be apparent and part pointed out in the following description'and drawings, in which:

Figure 1 is a top facsimile recorder utilizing the principle of my invention.

Figure 2 is a side view of ure 1.

Figure 3 is an end view of the apparatus of Figure 1.

Figure 4 is a cross-sectional view 6-6 of Figure 3.

Figure 5 is an end view 5-5 of Figure 1.

Figure 6 is a view partly in cross-section show- -ing the front of the scanner and is taken from line 6-6 of Figure 1. g Figure '7 is a view partly in cross-section taken along line I-l of Figure 1 showing the resettingmeans for the stylus.

Figure 8 is a cross-sectional view taken along line 8-8 of Figure'G.

Figure 9 is a. top view artly broken away taken along the line 9-8 of Figure 11.

the apparatus of Fi taken on line taken along the line Fi line ill-IQ of Figure 1.

Figure 11 is a cross-sectional view taken along line H-ll of Figure 1 showing the paper feed.

Figure 12 is a cross-sectional view taken along line i2-l2 of Figure 10.

Figure 13 is a cross-sectional view taken along line i3-l3 of Figure 2 showing the chain and sprocket drive.

Figure 14 is a cross-sectional view taken along line i i-l6 of Figure 13.

Figure 15 is a cross-sectional view taken along line 15-15 of Figure 2.

Figure v16 is a cross-sectional view taken along line "5-16 of Figu e 1.

Figure 17 is a cross-sectional view taken along line Il-Ii of Figure 1.

Figure 18 is a cross-sectional line i8-l8 of Figure 17.

view taken along Figure 19 is a view of the portion of the paper surface contacted by the stylus and showing guides for the scanning stylus of Figure 1.

Figure 20 is a. cross-sectional view taken along line 20-20 of Figure 19.

Figure 21 is a cross-sectional view taken along line 2l-Zl of Figure 19. p Figure 21a is a view corresponding to a portion of Figure 6 showing a modified form of relay construction.

Figure 21b is a cross-sectional view of line 2!!)- 2ibofFigure2la.

Figure 22 is a top plan View of light beam scanner recorder utilizing the principles of the present invention.

Figure 23 is an end view partly in cross-section taken along line 23-23 of Figure 22.

Figure 24 is a cross-sectional view partly in elevation taken along line 25-23 of Figure 22.

Figure 25 is a cross-sectional view partly in elevation taken along line 25-25 of Figure 22.

Figure 26 is a cross-sectional view taken on line BEE-2t of Figure 22;

Figure '2'? is a view eorresponding'to a portion of Figure 23' showing another position of the parts thereof.

Figure 28 is a view. corresponding to a portion of Figure 26 showing another position of the parts thereof 1 Figure 29 is a top plan view taken along line 29-29 of Figure 23 showing one position of the synchronizing elements.

Figures 30, 31,32 and, 33 correspond to Figure 29 showing the difierent positions of the parts thereof.

Figure 34 is a top plan view of an apparatus illustrating a modified application of my invention to an oscillating arm scanner.

' e 35 is an elevation partly in cross-section taken along line 35-35 of Figure 34.

Figure 36 is a. cross-sectional view taken along line 36-36 of Figure 34. t

Figure 37 is an enlarged view Figure 35.

Figure 38 is a top plan view illustrating-a slight modification of the construction of Figure 5-4 as likewise applied to an oscillating scanning arm.

Figure 39 is a cross-sectional view partly in of a portion of f elevation taken on line 39-39 of Figure 38.

Figure 40 is a cross-sectional view partly in elevation taken on line 40-40 of Figure 38.

Figure 41 is an enlarged view of a portion of Figure 40.

Fi ure 42 is a view taken along line 42-42 of Figure 38. I

gure 10 is a cross-sectional view taken along I Referring now to Figures 1, 2 and 3, the recorder of this embodiment is arranged for compactness and simplicity of construction and operation consistent with quality high speed recording. The recorder may be designed for mounting in a portable cabinet of a type and size similar, for instance to a radio console cabinet, a suitcase or other similar stationary or portable article. The recorder arrangement may also be designed for directly viewing the recorded matter as the recording progresses.

The multistylus drive assembly may, if desired,

, be mounted upon a cast iron base 50 (Figures 1 and 3). An endless belt or sprocket chain Figures 1 and 2) is used as a carrier for the individual styli assemblies 52 (Figures 2 and 3), and is driven by sprocket gear 53 (Figure 1) cooperating with idler sprocket 54. preferably of such'length that it is relatively taut between the sprockets and the sprockets are correspondingly spaced forthis purpose.- The styli assemblies 52 are mounted at equidistant points on the chain 5| at intervals substantially equal to the width of the recording sheet 55.

Stylus assemblies 52 are movable in a plane parallel to the base 5|! and individually and suc-'- cessively cooperate with the recording sheet once for each revolution of the chain 5|.

An electric motor 56 is supported beneath the recorder base 50 by bracket 51 which in turn is secured to the under side of the recorder base by the bolt 58. Motor 56 is preferably of the nonsynchronous type operable from an alternating or direct current power supply.

Motor 56 is coupled to a drive shaft 83 through worm gear arrangement enclosed in housing 66 shown in section in Figure 13. Any suitable connection may be made between the motor 56 and the arrangement enclosed in housing 68. A preferred form shown particularly in Figure 2 is the flexible cable 6| which is used to connect the motor shaft with the gearing arrangement.

The synchronizing magnet 1| supported beneath the base 56 as seen in Figures 2 and 13 is responsive to received cyclic impulses and coop crates with the driven mechanism to establish a proper phase position for each stylus of each of the stylus assemblies 52 at the beginning of each recording excursion of each of the stylus assemblies.

This cyclic synchronizing action which constitutes the major portion of this invention will be hereinafter described in greater detail and will be more fully understood when the action of the various parts of the recording unit is first explained.

The motor 56 through the flexible cable 6| drives the worm 80 within the housing 6|]. This worm 80 meshes with the worm gear 8| which by means of the key 82 is mounted upon the drive shaft 83 in such manner that rotation of the worm gear 8| results in rotation of the shaft 83. The shaft 83 is positioned by and rotates in the journals 84 and 85, the end 86 of the shaft 83 being captured in the collar'81, which is connected thereto by the pin 88.

Compression spring .89 is located on, the shaft 83 between the collar 81 and thethrust bearing 96 and thus serves accurately to position the shaft 83. while it rotates and thus serves further to reduce any possible frictional loss at the base 0f the housing. I

This collar bears against the thrust bearing 34 The chain 5| is which in turn carries the thrust of the end of the shaft 9| Compression spring 89 thus accurately positions the shaft 83 against the two thrust bearings and the thrust bearings 90 and 94 serve =to isolate the shaft 83 from the remainder of the mechanism and make it possible to provide a releasable drive or clutch 95 for the sprocket 53. While this releasable drive or clutch 95 ap ears in Figures 3 and 13, it is shown most clearly in Figur 4 and will be hereinafter described in connection with the further description of the process of obtaining and maintaining synchronism.

The sprocket 53 is not driven directly by the shaft 83 but instead is driven by the hollow shaft or sleeve I00 (Figure 13) which rotates about the shaft 83 and which is independent of shaft 83. Shaft Hi0 carries at the upper end thereof, as seen in Figure 13, an insulating sleeve |0| which is secured thereto in any suitable manner as, for instance, by the screw )2. The insulating sleeve |0| has a peripheral extension 03 thereon which, by means of the screws H34 carries the sprocket 53. The sprocket 53 is thus insulatedly supported upon the shaft Hill and when the shaft I00 is driven, the sprocket 53 is caused thereby to rotate and hence to move the chain 5| in the appropriate direction as is hereinafter described.

Appropriate bearings 5 may be provided for the sleeve 00 in suitable extensions or mountings N6 of the base 56. The track member mounted on the insulating support ||B,'servs as a guide for the stylus assemblies in the manner hereinafter described; these members, for this purpose, extend longitudinally along the path of the "stylus assemblies and guide the assemblies around the sprockets.

The driven synchronized shaft carries a spiral gear |2li (Figures 13 and 3), which drives the gear IN. The gears I26 and |2| are the source of power for the paper drive and hence ensure that the movement of the paper will be exactly synchronous with the operation of the scanning device.

The gear |2| is keyed to the rod E22 which is mounted in suitable bearings M3 and i2 3 on the under sidev of the base 56. .The rotation of the rod I22 results in rotation of the worm at the opposite end thereof, 25. This worm meshes with the gear |36 which in turn is keyed to rod I37 and hence rotates the same. (See Figure 1|) as well as Figure 3.)

Rotatable rod I37 is mounted in appropriate bearings I and |4|,,the bearing I40 being secured by screws M2 to a bracket I43 which in turn is supported on the base and the bearing |4| being provided by a suitable bore in the base '50 In a suitable embodiment of this form of the invention. as shown in Figure 3, a supporting cabinet indicated by the dotted lines of said figure may be used. Th recorder 'base 50 sets into recesses at the top corners I10 of the bottom section I'M. A removable cover H2 is fitted onto te bottom section of the cabinet A transparent window ||3 may be set above the record? ing area in order to permit, direct viewing of the recording as it is performed; the transparent window may simply be an opening or may havea glass or any other transparent protective surface.

- the facsimile unit A roll of sensitized paper 206 is mounted beneath the recorder base 58 between the brackmit the insertion of the roll of recording paper without'otherwis making it necessary to disassemble the recorder.

Gear 260 is driven through the idler gear 278 by the gear 2?! which in turn i mounted upon and rotates with the shaft of the feed roller 952. The gearing ratio between the gear 21! and the gear 260 is designed to overdrive take up roll 238 to maintain a constant tension in the record sheet 55 during the normal feeding operation of The recording sheet 55 passes from the roll 28D around the platen 2t? over the drive roll I52 and onto the take up roll 238 (see also Figure a plurality of spaced rollers 20s, Figures 1, 2,

and 11, preferably of rubber are arranged on a' rod 209 in such a'manner as to press the record sheet 55 against the feed roller I62 during the recording operation. The pressing rod 209 is mounted at either end in sockets 2 I B of the brackets 2. The brackets 2H are mounted on the ends of the rod 2&2 (see dotted lines of Figure 1).

Spiral spring 2l3 is at one end secured at 2M to the rod 2 l2 and at the other end at 2 i5 biases the brackets 2! l in uch direction as to press the presser rod 209 upon the feed roll I62 and hence to force the rubber rollers 2118 upon the feed roll.

A crank arm 220 isprovided for separating the rubberrollers 208 from the feeding roll E52 when it is desired to thread the sheet 55 between the spring biased pressure rolls 208; andthe feed roller I62. As seen in Figure 3, a cam or eccentric'ally positioned disk 22l is arranged on the axis of support of the lever or crank arm 220 againstthe mechanical bias of the springs 2i3 and thereby rotating the brackets 2 l l and moving the pressure roller 208 away from the feed roller W2. 1

In order further to assist in the threading recording.

A frictional slip occurs at the over driven feed roll 238 to keep sheet 55 taut as will be further described in detail in connection with Figures 16 and 17. The feed or drive roll IE2 is operated through the gear it] as heretofore described particularly in connection with Figure 10. Figure 10 shows in section the connection between the gear i6! and the shaft 280 of the feed roll 562.

The roller M52 is secured by pins 28! or any other suitable means to the shaft 280, the said pawl 285 is mounted near the periphery of the gear l6! and an associated'ratchet 286 is pinned to the extension'290 of the haft 286. in order to efieot a positive drive connection between the gear l6! and the roller shaft 281].

The surface of the feed roll 562 is metallic in order to afford a continuous electrical contact 5 to the recording sheet for electrochemical recordoperation, a knurled hard rubber knob 2319 (Fig-, 4

me 2) may be secured to the left end of the shaft supporting the feed roller 652.

driven and record sheet may be advanced until all the recorded matter'projects beyond the pressure rollers 208.

The recording sheet may then be torn at the region beyondthe pressure rollers and the recorded matter; may then be withdrawn from by removal of the. take up roll 238.

As is seen in Figures 16 and 17, the take up roll 288 is removably supported by the drive shaft 240 and the tail stock 23! as will be hereinafter more specifically" pointed out.

The recording paper in the present invention is positively fed in the appropriate directioii for successive line by line scannin'g -and the tension is uniformly maintained across the recording region of the recording sheet 55. no matter how; wide the particular sheet mayjjbe As shown in Figure 18, the free'end 250 of the recording sheet 55 is inserted iii the slot 25l in. thesp'ool 252 of the take up roll 238. The take up roll 238.15 mounted for rotation between the frame up-rights |43-l43 by means of the driving shaft or plate 240 and the tailstock arrangement 2. Drive shaft or plateflll is connected with the gear 260 through the friction clutch 26 l262 as seen in Figures 1 and '16.

\ By turning the knob 23d feed rollers I 562 may be independently ing action. The metallic portion'of feed roll 562 is connected to ground or frame potential forming the opposite potential to that of the stylus assembly. As seen in Figure 12, engagement of pawl and ratchet 285-285 occurs when the gear i5! rotates-in a counterclockwise direction. A positive drive is thus effected between the gear res and the drive roller i622 in the proper counterclockwise direction during the continuous feeding of the record sheet 55 while a recording being made thereon. v

When the knob 235 as seen in Figures 1 and 2 is manipulated to turn the shaft 2% counterclockwise, that is in the sheet feeding direction,

nection with Figure 1. Any recorded matter on sheet 55 may thus be manually advanced onto the take up roll 236 for removal from the facsimile unit. 7

' Each stylus of the present invention is rigidly guided when it is in recording position. In the present embodiment three individual stylus assemblies 52 are shown mounted on the link belt or chain 5| at equidistant spacings substantially corresponding to the width of the recording to be made upon the sheet 55. After one stylus has passed through the recording excursion, the next successive stylus is thus in position for starting its recording excursion. The link belt 5| affords a rigid positive driving means for the styli.

The whole mobile stylus assembly including the chain drive El and sprockets 53 and 54 and the guide roll 30!! are insulatingly mounted with remember 302 with respect to the rod 303. The slot 33| in the base 50 permits the member or base of the unit which is at ground potential.

The stylus assembly is insulated from the frame and is at the opposite potential.

In order to ensure a rigid linear path for each stylus during the recording excursion, means are provided for maintaining the chain at a predetermined tension or tautness. This means is provided at the left end of Figure 2 where means for maintaining the predetermined tension in the link belt or chain 5| areshown.

Post 30l carrying the sprocket 54 is carried by an adjustable member 302 which is secured to the rods 303 and 304 which rods are in turn slidably mounted in the openings 305, 306, 301, 308 of the brackets 309 and 3|0 which latter are in turn secured to the under side of the base 50.

A compression spring 3|5 is arranged to mechanically bias a rod 304 and hence also the member 302 towards the left of Figure 2. Spring 3|5 is so designed that its force will be sufiicient to keep the belt or chain properly taut for carrying the stylus assemblies 52 successively intheir recording path by tending to drive the sprocket 54 on,

its slidable mounting away from the sprocket 53.

Any temperature variation-or any other variation which would tend to expand or contract the belt 5| or any wear which may occur in the chain or belt 5| may automatically be'eompensated for by the continuous automatic action of the spring After the chain 5| is mounted upon the sprockets 53 and 54 set screw 230 should be clear of the member 302 after proper adjustment has been effected in order that biasing action of the spring 3|5 may be efiective to maintain proper continuous adjustment of the chain .5|.

Figure is a cross sectional view along line l5-|5 through the compensating mounting for the sprocket 54. Sprocket 54 is secured to the insulating post or hub 30| having a concentric bushing 325 rotatably mounted on the rod 326.

of the opposed set screws 329 and 330 which provide for a variable positioning of the slidable 302 to slide back and forth in response to the various tensioning eifects exerted between chain 5| and the spring 3|5.

As seen in Figures 9 and 11, the stylus assembly 52 is mounted on the chain 5| in any suitable manner as, for instance, by a pair of pins 400-400 which pass through the openings in the chain originally'designed for the link pins thereof and which are'engaged in the brackets 40| and 402 of the main stylus assembly support 403. The main stylus assembly support 403 has an additional front bracket 404' forming a U-shaped channel 405 between the bracket 404 and the main support 403.

A similar complementary U-shaped channel 406 is formed at the top of the main stylus support 403 by the plate 401 having the angular dependent flange 408 at one side thereof and the additional flange 409 at the opposite side which registers with the chamfered side 0 of the bracket 40L Screws 4 pass through openings in the plate 401 into the main support 403. Compression springs 4|2 are captured between the heads of .each of the screws 4| l and the upper side of the flange plates 401 thus pressing the plate downwardly and serving to tend to narrow the distance between the base of the U-shaped channel 406 and the base of the U-shaped channel 405.

A slidable stylus support 420 having projecting rails 42| and 422 is mounted on the main stylus assembly support member 403, the rails 42| and 422 being engaged in the U-shaped channels 405 and 406. The slidable stylus support carries a rotatable stylus 425 which is mounted on the shaft 426 which in turn is rotatably carried in the brackets 421. The brackets 421 are as is seen particularly. in Figure "1 extensions of the pivotally mounted member 428 which, as seen in Figures 9 and 11, is spring biased by means of the spring 429 towards such position that the stylus 425 is forced outwardly from the stylus supporting member 403.

The slide 420 which supports the stylus is slidable'in the channels 405 and 406 and is frictionally retained in such channels by means of the spring pressure of spring 4|2 upon the plate 401 which tends to narrow the distance between the bases of the said channels.

That is, although the slide which supports the stylus may move longitudinally with respect to the channels nevertheless the frictional engagement is such that the slide 420 tends to remain in said position with respect to'its support member 403.

The support member 403 carries on the under side thereof the slotted pulleys 430 which engage the rail 1 mounted upon the insulating support H8. These slotted pulleys 430 serve to position the front of the stylus assembly with respect to the rail. The rail of the stylus assembly carries the conical pulleys 43| mounted on the post 432 extending downwardly from the bracket 402.

A compression spring 433 is placed between the under side of the conical roller 43| and the head 434 or the post 432 and serves to bias the conical roller 43| so that its apex tends to ride close to the under side of the bracket 402. The conical roller 43| thus serves to support the opposite side of the assembly on the rail I I1 and as seen in Figures 9 and 11, an opening 435 may be provided in the bracket 402 of the stylus assembly and a. set screw 436 may be inserted therein in order to adjust the height of the bracket 402 above the rail 1. The base of the set screw 436 has been smoothed to minimize the frictional restraining forces between this screw .and the rail 1. The brackets 40| and 402 are so arranged that a channel 440 is formed therebetween, the said channel registering with the periphery of the sprockets 54 and 53 when the stylus assembly and the portion of the chain upon which it is mounted passes over the said sprockets, the said channel 440 receiving the said sprockets and the stylus assembly being thereby so arranged that it will not in any way interfere with the operation of the chain.

In suitable cases where that may be desirable, the lower rail 422 of the stylus carriage 420 may, as is seen in Figures 5 and '1, have a series of teeth 450 therein forming a rack. A gear segment or wheel 45| is pivotally mounted at 452 upon a de.

pendent bracket 658 supported by the main support M33 of the stylus assembly, the said gear segment 615i meshing with the rack Q50 and being so arranged that rotation of said gear segment will result in corresponding movement of the rack d50- and a corresponding sliding motion of the stylus carrier 528 within the channels 4305 and 306 of the stylus assembly 52.

The chain is so arranged that when the picture is being received, the said chain is always in continuous motion without any necessity for the chain or any portion of the driving mechanism thereof to come to a stop at that time.

Nevertheless in spite of this fact the arrangement of the present stylus and the cooperating synchronizing elements hereinafter described is such that synchronization may be had for each scanning excursion of each stylus and the actual rolling stylus 325 may be brought to a stop for the purpose of obtaining such synchronization without the necessity for stopping even the stylus assembly itself or anything connected therewith.

In other words, the synchronizing apparatus of the present invention does not coact with any of the driving elements whatever of the sprockets and the chain itself and even the movement of the stylus assembly and the supports thereof is constant and continuous during the recording.

' The slidability of the subsidiary stylus carriage 520 within the U-shaped channels 505 and 41036 is the sole means of permitting synchronization. The relative mass of the stylus carriage 320 and the associated stylus 525 is, it will be noted, so small that the momentary stopping of thestylus carriage lZll for the purpose of synchronizing will not have any vibratory or disrupting eifec't of any nature whatsoever upon the pictureor upon th recording operation.

' arranged that the portion 458 thereof is ofv 458 is to rotate in a clockwise direction with re- In other words, instead of having the synchro nizing operation take place in such manner that the moving mass of the chain and all of the stylus supports and sprockets which drive the chain as well as the shafts which drive the sprockets are brought to a stop, it is necessary only to interfere with the forward movement of the stylus can.

riage 120 momentarily until the receipt of the synchronizing impulse in order to obtain the necessary synchronization.

Accordingly, as is seen in Figures 6 and 8, the synchronizing apparatus operates only upon the subsidiary stylus carriage 320 and does not interfere with the operation of any other portion of the mechanism and in fact is so arranged that should there be any tendency for it to interfere in any'other portion of the mechanism or should the stylus carriage 320 be moved to such position that it may tend to-be removed irom the main support 403 of the stylus assembly 52, then the hold upon the stylus carriage will be released so that the stylus carriage might proceed with the remainder of the mechanism.

As is seen in Figures 6 and 8 the synchronizing mechanism comprises the synchronizing magnet H which is mounted in any suitable manner as for instance on the bracket 68! which is in turn supported from the base 59 of the mechanism. The electromagnet H is arranged to coact with and when energized'to attract the armature 662, the said armature 462 being pivoted at 653 and being biased by the tension spring 554 away from the magnet H. The tension spring 565 is connected at one end to the pin #365 of the armature I 4362 and at the other end is connected to the pin M55 which is mounted upon the bracket 38? which in turn is also supported from the base 60.

' as'zaers The synchronizing lever 5391s pivotally mounted on the, pin 559 which is also supported on the.

bracket ltl. The synchronizing lever lttjis so greater mass: and weight than the portion 568a thereof so that the natural tendency-of the lever weight would otherwise createby the pin ilt of the protective lever ill which is also pivoted on the pin 169. The protective lever dii also comprises two'arms, one arm fill .having increased mass or weight and the other or tripping arm Mia being of lesser mass or weight, the arms of the lever All being .so arranged that the two are I normally biased to rotate in clockwise direction with respect to Figure 6.

The possible clockwise rotation of the protective lever lli is inhibited by the stationary pin 1712 which is mounted upon the bracket. Thus immediately before the synchronizing impulse-is received, the synchronizing lever M8 is arranged in the position shown in Figure 6 where its aim 5568a is disclosed in the path of the subsidiary stylus carriage 520 while its arm 388 is. supported on the pin 6700f the protective lever lli. The protective lever ill-i is so arranged that its arm ill la is in the path of the main portion of the stylus assembly 52 and its other arm ill issupport'ed on the stationary pin M2.

The arm 668a of the synchronizing lever S6 8 as well as the arm c'ila of leverportion 1! project through the opening 4180 in the base 59, the

said opening being sufiiciently largeto permit.

of the operation hereinafter described.

The arm 681: is. arranged at the beginning of the scanning excursion, that is, it is, with re spect to Figure 1, set at the left hand side of the sheet 55. Thus it is arranged so that it will a interrupt the movement of the stylus carriage #20 at the beginning of each' scanning excursion.

spect to the left hand side of the sheet and hencestationary with respect to the beginning of the scanning line.

Accordingly, owing to the continued movement of the chain 5i and of the remainder of the stylus assembly 52, the-subsidiary stylus carriage e20 will slide in the U-shaped channels 565 and 608 of the main stylus assembly. and will continue to slide therein, m'ovingoutwardly as, for

instance, shown in Figure 6 until the synchronizf ing impulse is received.

Thus, for instance, as seen in Figure 6, should:

the subsidiary stylus carriage Mt have originally so arranged that it will abut'against the leading edge of the subsidiary stylus carriage are and hold the said subsidiary stylus carriage d2!) stationary with re-.

projected outwardly from the leading side of the stylus assembly 52 and should the entire stylus assembly 52 have reached the synchronizing arm 468 so that the leading edgeof the subsidiary stylus carriage 420 contacted the said arm at the time when the right hand end of the stylus assembly 52 wasin the position shown by the dottedlines, then although the stylus assembly 52 and the chain will have nevertheless continued their movement to the position shown by the solid lines, the subsidiary stylus carriage by reason of the fact that it was thus held stationary will have with respect to the stylus assembly 52, been apparently moved backwards to await the .synchronizing impulse which would permit it to commence its-scanning excursion.

In order to eflfect this operation the arm 468' of the lever 468 is held against counterclockwise motion under the influence of the force supplied by the stylus assembly 52 to the subsidiary stylus assembly 420 by. the detent 48l in the armature 462 which engages the pawl 482 at the end of the arm 468',

On receipt of a synchronizing impulse, the

vmagnet H is energized and attracts the armaassembly and to move the. lever arm 468a. out of the way when the opposite end 48I of the lever 468 is not engaged by the detent 48L Accordingly, upon receipt of the synchronizing impulse the ability of the lever arm 468 to impede the movement of the subsidiary stylus carriage with its stylus assembly is terminated and therefore immediately upon the receipt of the synchronizing impulse the subsidiary stylus carriage 420 starts to move with its stylus assembly and commences the scanning excursion at the beginning of the scanning line.

The one danger that may arise where a nontechnical or home user is operating the recording unit is that improper or unpracticed operation thereof may possibly result in the withdraw" ing of the subsidiary stylus carriage 420 from the stylus assembly 52; but the lever arm 411 is provided to obviate this possibility.

The arm 4'Ha of the lever 41! is so arranged that it will contact the main or unslidable portion of the stylus assembly. When the main portion of the stylus assembly strikes the arm 4'Ha,

' it will causethe said arm to rotate in a counterclockwise direction. The chamfered portion 485 of the arm '4'H of the lever 4' will then'strike the pin 486 of the armature 462 and owing to the counterclockwise rotation of the lever 4H move the pin towards the synchronizingmagnet 'H and accordingly therefore likewise move the armature 462 in that direction in order to disengage the pawl 482 of the arm 468 of the lever 468, thus releasing the subsidiary stylus carriage 420 from the stopping action of the arm 468a and hence permitting the stylus carriage to continue its movement with the stylus assembly 52.

The arm "In of the lever "I is so spaced and arranged that it will not merely engage the main portion otthe stylus assembly 52 but also that it 505 in order to energize the styli and to record will engage said portion or the stylus assembly 52 only after the subsidiary stylus carriage 420 has had an opportunity to traverse a substantial portion of the channels 405 and 406 in the attempt to reach synchronism.

Accordingly, in ordinary operation unless substantial accidental misphasing of a serious and unusual type should occur the arm 4'lla should rarely come into operation for the purpose herein described but it is present as asafety factor in order to prevent the subsidiary stylus carriage I rent must' be made to flow through the magnet II in time to receive the synchronizing impulse.

Accordingly, the driven shaft I00 (Figure'13) of the sprocket 5 3 which drives the chain carries a cam 500 (Figures 13 and 14) which is arranged to disconnect the current from the stylus assembly and to make the circuit to the synchronizing magnet whenever a scanning excursion is completed and whenever asynchronizing impulse is thus to be received.

The cam 500 has a lug 50! extending therefrom for this purpose. A rod 502 is carried in an opening 503 of the base 50 and is so arranged that one end thereof bears against the cam v500 and the other end thereof bears against the central contact 504 of a cam switch 505.

The central contact 504 of the cam switch 505.

is spring biased in such manner that it tends always to drive the rod 502 against the side of the cam 500. Normally the current flows from contact 504 into contact 506 of the cam switch the picture modulations upon the recording sheet 55.

The cam 500 is so arranged that upon completion of the scanning excursion a lug 501 has driven'the rod 502 to the position shown in Figure 14 where the contact 504 is en aged with the contact 501 which energizes the synchronizing magnet and thus permits the synchronizing impulse to be received and to be impressed upon the synchronizing magnet and hence to permit the starting of the scanning excursion at the proper moment.

In order for the lug 501 to be in position at the termination of each'scanning excursion, a single revolution of the sprocket wheel .53 must represent the length of a scanning line. Thus. the circumference of the shell must equal the linear scanning distance.

By means of this arrangement only the stylus that for most practical purposes and ordinary.

utilization. of my invention the circuit will be changed so that the synchronizing means will be energized by the synchronizing impulse and so 1 that the current will not flow through the styli when the synchronizing impulse is received.

In actual practice, the subsidiary. 

